1. Field of the Invention
The present invention relates to an image processing apparatus, an image forming apparatus, and a computer-readable recording medium storing an image processing program, which create a document image by superimposing a special dot pattern or a pattern image, which includes predetermined information, onto an image shown by inputted image data.
2. Description of the Related Art
In recent years, there has been known a method for managing a document by printing a special dot pattern, which includes document creating information, copy information, or information for preventing copying of a document, together with a document image (refer to Japanese Unexamined Patent Publication No. 2003-101762). Also, there has been know a method for preventing unfair copying and distinguishing an original from a copy by printing a pattern image, in which warning characters appear if a document is copied with a copying machine, together with a document image.
However, in a case where a document image includes picture images such as a photo and an image, if the special dot pattern and the pattern image are superimposed onto a whole document image, an image quality of a printed picture image is degraded.